The present invention is directed to a cutting apparatus and, more particularly, to a cutting apparatus for a progressing cavity pump.
A typical progressing cavity pump (i.e., a helical gear pump), such as a model 2000 pump sold by Moyno, Inc of Springfield, Ohio, includes a rotor having one or more externally threaded helical lobes which cooperate with a stator having an internal bore extending axially therethrough. The bore includes a plurality of helical grooves (typically one more helical groove than the number of helical lobes of the rotor). Progressing cavity pumps are discussed in greater detail in U.S. Pat. Nos. 5,722,820, 6,120,267 and 6,491,501, the entire contents of which are incorporated herein by reference.
Pumps of this general type are typically built with a rigid metallic rotor and a stator that is formed from a flexible or resilient material such as rubber. The rotor is made to fit within the stator bore with an interference fit such that there is a compressive fit between the rotor and stator. This compressive fit results in seal lines where the rotor and stator contact. These seal lines define cavities bounded by the rotor and stator surfaces. As the rotor turns within the stator, the cavities defined by the seal lines progress from the suction end (i.e., inlet) of the pump to the discharge end (i.e., outlet) of the pump.
A typical progressing cavity pump may be used to pump a wide variety of fluids including solids, semi-solids, fluids with solids in suspension, highly viscus fluids and shear sensitive fluids. However, it is often difficult to introduce certain materials into the cavities between the stator and rotor during pumping operations.
Thus, the pump may be connected to a feeder that supplies materials to the pump inlet. The feeder may include a hopper and an auger. The hopper may include an inlet and an outlet such that material introduced in the inlet can be urged through the outlet of the hopper (i.e., to the inlet of the pump) via the auger. However, such feeders may be ineffective when large solid and semi-solid materials are introduced into the hopper.
Accordingly, there is a need for an apparatus for reducing the size of materials placed into a feeder, thereby allowing the feeder auger to transport the materials to the inlet of a progressing cavity pump such that the smaller sized materials can be pumped.